As disclosed in JP 2001-349413 (A) and JP 2003-232433 (A), one-way clutch integrated pulley devices have been conventionally used as pulley devices for driving auxiliary machines, such as an alternator, for an automobile.
FIG. 8 illustrates an example of conventional construction of rotary machinery with this kind of one-way clutch integrated pulley. A rotary machine 1 such as an alternator normally has a housing 2, and a rotating shaft 4 that is supported inside the housing 2 by way of a support bearing 3 so as to be able to rotate freely. An inner ring 5 of the support bearing 3 is fastened with an interference fit around the outside of the middle section in the axial direction of the rotating shaft 4 and an outer ring 6 of the support bearing 3 is fastened with an interference fit on the inside of the housing 2. In this state, in order to position the support bearing in the axial direction, one end surface (right end surface in FIG. 8) in the axial direction of the inner ring 5 comes in contact with a stepped section 7 that is provided around the middle section in the axial direction of the rotating shaft 4, and the other end surface (left end surface in FIG. 8) in the axial direction of the outer ring 6 comes in contact with an inward facing flange section 8 that is provided on the housing 2. In other words, the support bearing 3 is held from both sides in the axial direction by the stepped section 7 and an inward facing flange section 8. The tip end section (right end section in FIG. 8) of the rotating shaft 4 protrudes to the outside of the housing 2. For example, when the rotary machinery 1 is an alternator, the rotating shaft 4 corresponds to a rotating shaft of the alternator, and when the rotary machinery 1 is an auxiliary drive apparatus during an idling stop of the engine or an electric motor, the rotating shaft 4 corresponds to a crankshaft of the engine or a drive shaft of the electric motor.
A one-way clutch integrated pulley 9 has a sleeve 10 and pulley 11 that are arranged concentric with each other. The sleeve 10 is such that by screwing a female screw section 12 that is formed around the inner circumferential surface in the middle section in the axial direction onto a male screw section 13 that is formed around the outer circumferential surface on the tip end section of the rotating shaft 4, the sleeve 10 is supported by and fastened to the rotating shaft 4 so as to be able to rotate in synchronization with the rotating shaft 4. With this kind of sleeve 10, by one end surface (right end surface in FIG. 8) coming in contact with the other end surface (left end surface in FIG. 8) of the inner ring 5 of the support bearing 3, it is possible to position the rotating shaft 4 in the axial direction. Moreover, the pulley 11 is arranged around the sleeve 10, and is provided with belt grooves 15 for a belt (continuous belt) 14 that is placed around a drive pulley (not illustrated in the figure) and that is rotated and driven by the drive pulley.
Moreover, a one-way clutch 16 and a pair of support bearings 17 are provided between the outer circumferential surface of the sleeve 10 and the inner circumferential surface of the pulley 11. The one-way clutch 16 is such that torque is transmitted between the pulley 11 and the sleeve 10 only when there is a tendency for the pulley 11 to rotate in a specified direction relative to the sleeve 10. The one-way clutch 16 has a clutch inner ring 18, clutch outer ring 19, a plurality of rollers 20, a clutch cage 21 and the same number of springs 22 as rollers 20. The clutch inner ring 18 is fastened with an interference fit around the outer circumferential surface of the middle section in the axial direction of the sleeve 10, and by providing long concave sections 23 called ramp sections, which are long in the axial direction and that become deeper while going in a specified direction in the circumferential direction, at a plurality of evenly spaced locations in the circumferential direction around the outer circumferential surface thereof, the outer circumferential surface functions as a cam surface 24.
The plurality of rollers 20 and the clutch cage 21, which supports these rollers 20 so as to be able to roll and to displace a little in the circumferential direction, are provided between the cam surface 24 and a clutch outer-ring raceway 25, which is a cylindrical surface that is formed around the inner circumferential surface of the clutch outer ring 19. Springs 22 are provided between column sections, which are provided at a plurality of evenly space locations in the circumferential direction of the clutch cage 21, and the rollers 20, and these springs 22 elastically press the rollers 20 in a specified circumferential direction. Alternatively, it is possible to provide ramp sections at a plurality of location in the circumferential direction around the inner circumferential surface of the clutch outer ring, and for this inner circumferential surface to function as a cam surface, and for the outer circumferential surface of the clutch inner ring to be simply a cylindrical surface.
The outer diameter of the rollers 20 is less than the space between the outer circumferential surface of the clutch inner ring 18 and the inner circumferential surface of the clutch outer ring 19 in the portions where the concave sections 23 are formed, and is greater than the space between the outer circumferential surface of the clutch inner ring 18 and the inner circumferential surface of the clutch outer ring 19 in the portions separated in the circumferential direction from the concave sections 23. The rollers 20 are pressed by the springs 22 so as to bite like a stopper into the portions between the outer circumferential surface of the clutch inner ring 18 and the inner circumferential surface of the clutch outer ring 19 that are separated in the circumferential direction from the concave sections 23 where the spaces between these surfaces become narrow.
Moreover, the pair of support bearings 17 make relative rotation between the pulley 11 and sleeve 10 possible, while at the same time support radial loads that are applied to the pulley 11. In the example illustrated in the figure, a deep-groove ball bearing that in addition to being able to support radial loads that are applied to the pulley 11, is also able to support axial loads, is used as this kind of support bearing 17. In other words, the support bearing 17 comprises an outer ring 27 that has a deep-groove outer-ring raceway 26 around the inner circumferential surface thereof, an inner ring 29 that has a deep-groove inner-ring raceway 28 around the outer circumferential surface thereof, a plurality of balls 30 that are provided between the outer-ring raceway 26 and the inner-ring raceway 28 so as to be able to roll freely, and a cage 31 for supporting these balls 30. The outer rings 27 are fastened around the inside of both end sections in the axial direction of the pulley 11. Moreover, the inner rings 29 are fastened around the outside of small-diameter stepped sections 32a, 32b that are formed on both end sections in the axial direction of the sleeve 10. Opening sections on both end sections of the cylindrical space where the balls 30 are located are covered by seal rings 34, the outer circumferential edge sections thereof fitting in fitting grooves 33 that are formed around the inner circumferential surface of the outer ring 27. These seal rings 34, together with preventing grease that is filled inside the cylindrical space where the balls 30 are located from leaking out, prevent foreign matter such as dust from getting inside the space.
In this kind of one-way clutch integrated pulley 9, when the clutch outer ring 19 rotates with respect to the clutch inner ring 18 in the same direction that the springs 22 press the roller 20, the rollers 20 bite between the outer circumferential surface of the clutch inner ring 18 and the inner circumferential surface of the clutch outer ring 19, and a locked state occurs in which the clutch inner ring 18 and the clutch outer ring 19 rotate in synchronization. On the other hand, when the clutch outer ring 19 rotates with respect to the clutch inner ring 18 in the opposite direction that the springs 22 press the rollers 20, the rollers 20 are located in the portions where the concave sections 23 are formed, and roll in those portions, and an overrun state occurs in which torque is not transmitted between the clutch inner ring 18 and the clutch outer ring 19.
This kind of one-way clutch integrated pulley 9, when assembled with the rotating shaft 4 of rotary machinery 1 such as an engine or auxiliary machine, is housed inside the engine room of an automobile. The size and shape of this kind of engine room differ depending on the type of vehicle. In other words, the positional relationship between the installation location of the rotary machinery 1 such as an alternator, and the location in the axial direction of the belt 14 that is placed around the pulley 11 differs depending on the type of vehicle. Therefore, the location in the axial direction of the one-way clutch integrated pulley 9 with respect to the rotary machinery 1 must be changed for each type of vehicle. In the case of this construction, positioning the one-way clutch integrated pulley 9 in the axial direction with respect to the rotary machinery 1 is possible by bringing one end surface of the sleeve 10 in contact with the other end surface of the support bearing 3 that supports and fastens to the middle section in the axial direction of the rotating shaft 4. Therefore, in order to change the location in the axial direction of the one-way clutch integrated pulley 9 with respect to the rotary machinery 1 for each vehicle model, it is necessary to prepare a plurality of different types of sleeves 10 having different dimensions for the small-diameter stepped section 32 that is formed on the one end as a special part. This causes a problem in that the manufacturing cost of the rotary machinery with a one-way clutch integrated pulley increases.